Understanding ratings

The IUCN World Heritage Outlook is based on Conservation Outlook Assessments prepared for each single natural World Heritage site. This includes assessments of the natural values of "mixed sites", which are listed for both natural and cultural significance. These desk-based assessments are a projection of the potential for a site to conserve its natural values over time, according to three main elements:

You can access each assessment by exploring the interactive map or through the filtered search. Below you will find a guide to understanding the rating categories used in the Conservation Outlook Assessments of natural World Heritage sites.

Rating categories for Conservation Outlook Assessments

Each Conservation Outlook Assessment has an overall rating. There are five rating categories, as defined below.

Rating

Definition

Good

The site's values are in good condition and are likely to be maintained for the foreseeable future, provided that current conservation measures are maintained.

Good with some concern

While some concerns exist, with minor additional conservation measures the site's values are likely to be essentially maintained over the long-term.

Significant concern

The site's values are threatened and/or are showing signs of deterioration. Significant additional conservation measures are needed to maintain and/or restore values over the medium to long-term.

Critical

The site's values are severely threatened and/or deteriorating. Immediate large-scale additional conservation measures are needed to maintain and/or restore the site's values over the short to medium-term or the values may be lost.

Data deficient

Available evidence is insufficient to draw a conclusion.

Rating categories values, threats and protection

To assess the overall outlook of a site, three elements are first examined and classified into rating categories.

1 Current state and trends of values

World Heritage sites are unique because they possess Outstanding Universal Value (OUV). When they are first inscribed on the World Heritage List, their OUV is considered intact.

All elements necessary to maintain the site's values are essentially intact, and their overall condition is stable or improving. Available evidence indicates only minor, if any, disturbance to the values of the site.

Low Concern

Some loss or alteration of the elements necessary to maintain the site's values has occurred, but their overall condition is stable or improving and is not causing persistent or substantial effects on the values of the site.

High Concern

Loss or alteration of many elements necessary to maintain site values has occurred, which is leading to a significant reduction in the values of the site.

Critical

Loss or alteration of a majority of elements necessary to maintain site values has occurred and has caused a major loss of the values of the site.

2 Threats

Like any natural area, World Heritage sites can be exposed to threats, both from within and outside their boundaries. These can be natural threats, such as environmental disasters, or man-made threats, such as infrastructure projects or poaching.

Rating

Definition

Very Low Threat

Few or no threats are evident and accepted predictions indicate that negative impacts on the site's values and integrity are likely to be minor.

Low Threat

Some minor threats are evident and there is concern that based on accepted predictions there are likely to be some localized but reversible negative impacts on the site's values and integrity.

High Threat

There are clear threats to the site, and current and/or predicted future impacts are likely to result in significant negative effects on the site's values and integrity.

Very High Threat

The threats to the site are very high, and current and/or predicted future impacts are likely to result in the irreversible loss of the majority of the site's values and its integrity.

Data Deficient

Available evidence is insufficient to draw a conclusion.

3 Protection and management

On-the-ground conservation of World Heritage sites must be backed by effective protection and management systems that meet the particular needs of each site.

Rating

Definition

Highly Effective

The protection and management system under implementation is effective and able to maintain the site's values and integrity. Aspects of site management can be regarded as being best-practice.

Effective

The protection and management system under implementation is adequate and is likely to essentially maintain the site's values and integrity over the medium-term. However, it may be insufficient to maintain the site's values and integrity over the long-term.

Some Concern

The protection and management system is not fully addressing the threats to the site's values, resulting in a number of conservation issues. However, these issues could be reversed and effectively addressed in the short-term if management capacity and/or protection are improved.

Serious Concern

The protection and management system shows major deficiencies and is unable to maintain the site's values and integrity over the short or long-term. Major interventions are required to enhance management capacity and/or protection.

Data Deficient

Available evidence is insufficient to draw a conclusion.

Additional information on benefits and projects

In addition to providing a global overview of the state of conservation of natural World Heritage sites, Conservation Outlook Assessments present an opportunity to collect additional information.

Each assessment contains a list of ecosystem services and possible benefits provided by a natural World Heritage site, with more detailed descriptions and an evaluation of the most relevant benefits and how they may be affected by threats. This information is useful when considering how sites can help support healthy ecosystems, which in turn provide life-supporting benefits to people, and may also help maintain World Heritage and other important biodiversity values over time.

Assessments also contain information on active conservation projects, and possible project needs, where this information is available. To date, there has been no systematic attempt to collect such data, and the IUCN World Heritage Outlook assembles this information for the first time.